Make Coverity work again after I keep messing it up

We should ensure the validity of three environment variables to prevent a later, more costly failure.
    
Currently, the 'after_script' section doesn't catch errors from the 'script' section, and I think the 'script' section doesn't catch errors from the 'before_script' section. Therefore, we must merge them to ensure that bad results are caught and reported.
    
We can significantly save time by eliminating the second 'apt update' call, getting 'eatmydata' earlier, and using it. Adding the 'ca-certificates' required by curl and temporarily dumping the headers from curl for diagnosis will further enhance the job's performance.

I wrote this post with too much input from an Artificial Intelligence program.